1. Technical Field
The present invention relates to an optical device, a semiconductor wafer, a method of producing an optical device, and a method of producing a semiconductor wafer.
2. Related Art
Japanese Patent Application Publication No. 08-274376 discloses a stack of three LEDs respectively emitting blue, green and red light, specifically speaking, full-color-display pixels including LEDs made of III-V nitride compound semiconductors that lattice-match silicon and are formed on a silicon wafer.
Local optical communication within a single semiconductor wafer has been demanded to realize high-speed communication of a large amount of data within the semiconductor wafer. The transfer rate of optical communication is dependent on the performance of optical devices such as light emitting and receiving devices. Thus, high-speed optical communication can be realized by using fast transistors to control discrete optical devices.
When fast transistors are used to control discrete optical devices, however, it has been difficult to realize improved switching rate of the optical devices and smaller circuits since longer interconnections are required between the transistors and the optical devices. Smaller circuits can be achieved by monolithically forming optical devices and transistors on expensive compound semiconductor wafers made of, for example, GaAs. When monolithically formed on low-cost semiconductor wafers made of, for example, silicon, however, optical devices and transistors cannot achieve performance suitable for high-speed optical communication.